Tubular anodes are widely used in cathodic protection, and may be formed of a variety of materials such as high silicon cast iron, graphite, carbon, magnetite, steel, titanium, niobium, and tantalum and alloys thereof. Titanium tubular anodes with mixed metal oxide exterior coatings are now employed. These tubular anodes are relatively long, yet of small diameter and fairly thin walled.
These mixed metal oxide anodes are used in deep or surface ground bed applications to protect pipelines, underground storage tanks, etc. from corrosion. A compression tool is used to establish an electrical connection from cable to anode at either one or both anode ends. During anode operation, problems associated with corrosion and ultimate penetration of these anode walls results in anode loss due to connection failure. This is extremely critical in the case of multiple anodes assembled on strings whereby one anode penetrated results in loss of succeeding anodes on the string.
In prior U.S. Pat. No. 4,515,669 dated May 7, 1985 there is disclosed a wedge type electrical connection which has been quite successful and widely used in relatively large diameter tubular anodes such as high silicon cast iron anodes. In such patent, FIGS. 8 and 9, there is disclosed an embodiment wherein the wedge parts are drawn together by a threaded stud, and a nut/cinch assembly. While this embodiment may have utility in fairly large internal diameter tubes, in a smaller and long tube it would have little practical utility.
Also, if a string anode is formed with the wedge connection of such prior patent, separate leads are required from anode to anode, requiring two lead connections, one to each part of the wedge connection. It would be advantageous if a continuous lead wire could be employed in a string with each anode connected electrically but once to the wire.
The present invention comprises then certain improvements in an anode and wedge connection such as seen in prior U.S. Pat. No. 4,515,669.